According to life-long Mortal Kombat shepherd Ed Boon, a PC version of MKAK never existed. This directly contradicts the fighter's original press release, which announced the title for "PlayStation®Network, Xbox LIVE® Arcade for the Xbox 360® video game and entertainment system from Microsoft and Windows PC." Additionally, a statement made to DSOGaming claims that the port has not been canceled, though no release date has been given.
It's a lot like Schrödinger's cat. We have no idea whether the project is dead or alive. We have reached out to Warner Bros. for comment.
Update: So when Ed Boon said that MKAK never existed, it turns out he actually meant that it totally exists, albeit with no announced release date.